Electroresponsive indicator



, Aug. 7, 1945.

c. c. WHITTAKE'R ELECTRORESPONSIVE INDICATOR Filed July 20, 1943 wl'TNEs Patented Aug. 7, 1945 l UNITED STATES PATENT OFFICE 2,381,326 ELECTRORESPONSIVE INDICATOR Charles C. Whittaker, Pittsburgh, Pa., assigner to f Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 20, 1943, Serial No. 495,444

1. Claim.

The invention relates to electroresponsive indicating instruments and more particularly to a device for indicating the magnitude of anvelectrical quantity of an electric circuit.

Although not limited thereto the invention was designed primarily for use on an electric klocomotive Where it is important that the load on the generator be maintained within predetermined limits, or that an excess load should be watched and reduced as soon as practicable.

Accordingly, it is an object of the invention to provide an electroresponsive indicator of simple and rugged design to indicate load conditions or other characteristics of an electric circuit.

Other objects of the invention will be apparent fromA the following description considered in connection with the accompanying drawing, in which;

section, yof an indicator constructed in accordance with the invention; and

, Fig. 2 is a view in Vertical section taken at right angles to the showing of Fig. 1.

Referring more specifically to the drawing, the indicator includes a base 2 having front and side walls 4 and 6, respectively, which encloses a pair of brackets 8 for supporting a'solenoid winding I0. y

Connection to the solenoid winding may be made through conductors I2 from the circuit to be measured ina usual manner. In the case of An indicating disc of a diameter to iit within the core of tubey rI4 relatively closely cooperates` with index marks 22 carried by index plates 24 secured by screws 26 in an offset portion of the lower bracket 8. A transparent window 21 (Fig. l) is provided in :the front wall 4 to permit observation of the armature position. f

When the device is calibrated so that the armature oats substantially in the position shown at a predetermined load current, any variation in such current will cause the armature to rise or drop below the index marks 22, thereby indicating to the operator whether the load current is above or below normal. In this iioating action the movement of the armature is dampened because the indicating disc substantially lls the rtube I4 with a loose sliding fit, and the tube is Figure l is a view-in side elevation, partly in f closed at both ends, as previously described.

Since the heat radiation, from the solenoid winding I0 and the copper cable from which it is energized are substantially the same, errors due to temperature coefficient of resistance are,

an electric locomotive, the conductors I2 are connected to spaced points on the generator cable to energize the winding in accordance with the IR drop in the shunted section of cable.

y A tube I4 of glass or other transparent material extends up through :the core of the solenoid, and is surrounded by an insulating tube I6 provided principally for cushioning the transparent g for practical purposes, eliminated.

By the-construction described an unusually rugged and ei'licient indicator is provided which is inexpensive to manufacture andsimple in operation.

Quiter obviously modications may be made -in the invention without departing from the scope thereof and it is intended that it be limited only by the scope of the appended claim.

I claim as my invention: v

In an electrical measuring device, a vertically mounted solenoid to be energized inaccordance with a quantity to be measured, a 'transparent tubular core for said solenoid having a portion depending therefrom, closures for the end of said core, an armature disposed in said core to be magnetically suspended by said solenoid and having an enlarged upper portion Within the solenoid tapering to a substantially smallerv lower portion visible vthrough the depending portion of said core, and an indicating dise coaxially mounted on said lower portion, the diameter of said disc being such as to guide the reciprocation of said armature and'damp the vertical movement thereof. v

CHARLES C. WHITTAKER. 

